Like several before have said, MR. SCARFACE IS BACK and THE WORLD IS YOURS are both classics. The only real difference between the two is that the first CD has a little bit more emphasis on samples (after all, this was 1991), while the second CD stresses live production (not too far off from what he did later on THE DIARY). Both approaches fit Scarface well.
MY HOMIES is kind of like the Yukmouth UNITED GHETTOS OF AMERICA collections, in that each song has Scarface rapping with different rappers, many who were on Rap-A-Lot with Face at the time: Big Mike, Willie D., the 5th Ward Boyz, Menace Clan (I THINK), Devin The Dude, 3-2, A-G-2-A-Ke (remember them?), to name a few. The production is really tight and the variety of artist rapping with Face is dope. I dig it.
LAST OF A DYING BREED's not a "first purchase", but it's cool once you have the others. I can't speak on BALLS & MY WORD, since I just haven't gotten around to picking it up, so you might want to listen to that one somewhere before you buy it.
PEACE!